Counterfeit documents are a serious problem for people who have to handle documents and supply goods or services in exchange for or as guaranteed by the documents. The most obvious examples are banknotes, bonds, share certificates and similar documents used in finance and banking, but problems also exist in other less spectacular situations such as forged gift tokens or tickets for a sporting occasion, concert or theatre. In all cases the chances of the counterfeit documents passing undetected are improved the more the person receiving the document is under pressure and therefore the less time the person has to notice or query a suspect document.
Moreover, as counterfeiting techniques have become more and more sophisticated it has become much harder for an untrained person to identify a counterfeit banknote quickly, particularly if the counterfeit note is only one of a number tendered simultaneously.
It is an object of the present invention to provide apparatus that can quickly and reliably detect a counterfeit document.